Honda Car Forum

I'm seriously considering buying an RSX Type-S and would like to know a
couple of things from people who own one, or have owned one. I read
somewhere that Acura recommends high octane fuel (91 if I remember
correctly) be used for the Type-S model. My question is What happens if
regular (87) octane is used instead? Can it cause any damage to the
engine? Will it reduce the gas mileage, and by how much? The second
question is what mileage per gallon are people actually getting with this
car? The sticker shows 23 City / 31 Highway, but my experience with the
1990 Honda CRX Si that I used to own proved that actual mileage can vary
quite a bit from what is reported on the sticker. I consistently got
between 36 and 40 mpg with my CRX, depending on the ratio of city to
highway miles, but the sticker said 28 City / 33 Highway.

Thanks, Joe

We leased a 2006 RSX-S one month ago. The car has 900 miles or three tank
fulls. So far the mileage has been 26, 28 and 29 mpg. The last on regular
fuel with no noticeable difference in performance.

The question of using regular 87 octane fuel in Honda cars that are
placarded as requiring premium (91 or higher octane) has been
discussed many times in this group.

Honda (Acura) firmly recommends premium only except in cases of
emergency, when regular can be used for a short period to get to a gas
station and a fill up with premium. The car must be driven "gently"
to reduce risk of detonation onset while regular is being used.

The issue here is compression ratio's and the very real risk of
detonation if a high compression ratio engine runs on a fuel with too
low an octane rating. There is no guarantee that detonation sensors
(sometimes called "knock sensors") will catch detonation and retard
fuel amounts and timing fast enough to save an engine when detonation
occurs. Detonation can destroy pistons, rings, valves, connecting
rods and rod bearings, basically trashing the engine and this damage
can occur in fractions of a second.

The cost of an engine replacement or rebuild would far exceed the
small additional cost of premium fuel over the life of the vehicle.

Finally, it would make no sense to put a fuel in a performance
oriented car which would then require you to drive it extremely gently
and at risk of blowing the engine at any moment.

I'll leave it to others to address the fuel mileage issue.

Paul



On Sun, 18 Jun 2006 22:14:50 -0700, Joe McArthur
<joemac@vfemail.spamblock.net> wrote:

>I'm seriously considering buying an RSX Type-S and would like to know a
>couple of things from people who own one, or have owned one. I read
>somewhere that Acura recommends high octane fuel (91 if I remember
>correctly) be used for the Type-S model. My question is What happens if
>regular (87) octane is used instead? Can it cause any damage to the
>engine? Will it reduce the gas mileage, and by how much? The second
>question is what mileage per gallon are people actually getting with this
>car? The sticker shows 23 City / 31 Highway, but my experience with the
>1990 Honda CRX Si that I used to own proved that actual mileage can vary
>quite a bit from what is reported on the sticker. I consistently got
>between 36 and 40 mpg with my CRX, depending on the ratio of city to
>highway miles, but the sticker said 28 City / 33 Highway.
>
>Thanks, Joe

if thats the case why does the manual say only that lower octane can be used
with reduced performance...nothing else is mentioned?


And if you are too cheap to get 91 octance fuel, just get the base RSX...

"Ramapo" <Unknown@verizon.net> wrote in message
news:vb9d92hf73kt6j2s8ghg5gei0g2eumvked@4ax.com...
> The question of using regular 87 octane fuel in Honda cars that are
> placarded as requiring premium (91 or higher octane) has been
> discussed many times in this group.
>
> Honda (Acura) firmly recommends premium only except in cases of
> emergency, when regular can be used for a short period to get to a gas
> station and a fill up with premium. The car must be driven "gently"
> to reduce risk of detonation onset while regular is being used.
>
> The issue here is compression ratio's and the very real risk of
> detonation if a high compression ratio engine runs on a fuel with too
> low an octane rating. There is no guarantee that detonation sensors
> (sometimes called "knock sensors") will catch detonation and retard
> fuel amounts and timing fast enough to save an engine when detonation
> occurs. Detonation can destroy pistons, rings, valves, connecting
> rods and rod bearings, basically trashing the engine and this damage
> can occur in fractions of a second.
>
> The cost of an engine replacement or rebuild would far exceed the
> small additional cost of premium fuel over the life of the vehicle.
>
> Finally, it would make no sense to put a fuel in a performance
> oriented car which would then require you to drive it extremely gently
> and at risk of blowing the engine at any moment.
>
> I'll leave it to others to address the fuel mileage issue.
>
> Paul
>
>
>
> On Sun, 18 Jun 2006 22:14:50 -0700, Joe McArthur
> <joemac@vfemail.spamblock.net> wrote:
>
>>I'm seriously considering buying an RSX Type-S and would like to know a
>>couple of things from people who own one, or have owned one. I read
>>somewhere that Acura recommends high octane fuel (91 if I remember
>>correctly) be used for the Type-S model. My question is What happens if
>>regular (87) octane is used instead? Can it cause any damage to the
>>engine? Will it reduce the gas mileage, and by how much? The second
>>question is what mileage per gallon are people actually getting with this
>>car? The sticker shows 23 City / 31 Highway, but my experience with the
>>1990 Honda CRX Si that I used to own proved that actual mileage can vary
>>quite a bit from what is reported on the sticker. I consistently got
>>between 36 and 40 mpg with my CRX, depending on the ratio of city to
>>highway miles, but the sticker said 28 City / 33 Highway.
>>
>>Thanks, Joe

On Mon, 19 Jun 2006 19:34:54 GMT, James said:

>And if you are too cheap to get 91 octance fuel, just get the base RSX...

Or get a Corolla.

--
Loud Pipes Risk Rights.

Joe McArthur <joemac@vfemail.spamblock.net> wrote in
news:Xns97E6E24F88F40ipdaily@216.168.3.44:

> I'm seriously considering buying an RSX Type-S and would like to know
> a couple of things from people who own one, or have owned one. I read
> somewhere that Acura recommends high octane fuel (91 if I remember
> correctly) be used for the Type-S model.



Correct.

87 is OK for other models. The Type-S MUST use 91.

All other models have a compression ratio of 9.8:1, which is already pretty
high, but the Type-S has a whopping 11:1 ratio! ELEVEN to one, people!
There was a time you never saw such a thing off the racetrack.



> My question is What happens
> if regular (87) octane is used instead?



According to the Owner's Manual, it can cause pinging and possible engine
damage.



> Can it cause any damage to
> the engine?



Yes, if you run into a bad batch that tests below 87.



> Will it reduce the gas mileage, and by how much?



Nobody knows. I suspect mileage loss would be slight.



--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

"James" <Private@email.com> wrote in
news:y%Clg.63039$I61.23550@clgrps13:

> if thats the case why does the manual say only that lower octane can
> be used with reduced performance...nothing else is mentioned?



Most Hondas are designed for 87 pump octane. The ones that are not have
very high compression ratios. Does YOUR car require 91 AKI? Look up your
Owner's Manual from Honda, here:
https://techinfo.honda.com/rjanisis/logon.asp
(You do not need to log in to access the Owner's Manuals, and there are a
few '07s available now).

The easiest way to find things in your Owner's Manual is to ignore the
Table of Contents and go straight to the Index at the back.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

On 2006-06-19 00:14:50 -0500, Joe McArthur <joemac@vfemail.spamblock.net> said:

> I'm seriously considering buying an RSX Type-S and would like to know a
> couple of things from people who own one, or have owned one. I read
> somewhere that Acura recommends high octane fuel (91 if I remember
> correctly) be used for the Type-S model. My question is What happens
> if regular (87) octane is used instead? Can it cause any damage to the
> engine? Will it reduce the gas mileage, and by how much? The second
> question is what mileage per gallon are people actually getting with
> this car? The sticker shows 23 City / 31 Highway, but my experience
> with the 1990 Honda CRX Si that I used to own proved that actual
> mileage can vary quite a bit from what is reported on the sticker. I
> consistently got between 36 and 40 mpg with my CRX, depending on the
> ratio of city to highway miles, but the sticker said 28 City / 33
> Highway.
>
> Thanks, Joe

Is the performance advantage over the base model worth the additional
expense, both up front and at the pump? Tough question, one I pondered
for quite a while. My decision was helped by running into a low mileage
base model at carmax, at a very low price. I had test driven a type s,
and was almost ready to go with it, but test driving the base model
pointed out something you can see in the specs, but might avoid seeing
if you've got type-s lust - in normal day-to-day driving on normal city
roads, there's virtually no difference in the performance.

Two other disadvantages of the type-s that're not immediately obvious -
the low frequencies from the exhaust make a significant difference in
cabin noise, and will cut your bass frequencies in your stereo. And the
stereo in the type-s is much harder to upgrade - if you actually like
the stock stereo, fine, but most music heads don't.

Mileage - my experience with my base model is that it's right exactly
what the sticker says, not significantly less, and certainly not any
better.

Thanks for the info. It looks like your mileage is improving as your
engine breaks-in. It's promising to hear that you were able to use
regular octane gas with no discernable problems. Although the guy who
replied right after you paints a bleak picture of doing that.

"Keyser Soze" <faradayincxxxspam@hotmail.com> wrote in
news:Kpxlg.6$jN6.3@fe09.lga:

> We leased a 2006 RSX-S one month ago. The car has 900 miles or three
> tank fulls. So far the mileage has been 26, 28 and 29 mpg. The last
> on regular fuel with no noticeable difference in performance.

Ramapo <Unknown@verizon.net> wrote in
news:vb9d92hf73kt6j2s8ghg5gei0g2eumvked@4ax.com:

> The question of using regular 87 octane fuel in Honda cars that are
> placarded as requiring premium (91 or higher octane) has been
> discussed many times in this group.

Before posting I searched back through Google a bit but didn't see
anything that answered my particular question.

> Honda (Acura) firmly recommends premium only except in cases of
> emergency, when regular can be used for a short period to get to a gas
> station and a fill up with premium. The car must be driven "gently"
> to reduce risk of detonation onset while regular is being used.

I managed to locate my RSX brochure and in the fine print it says:
"Gasoline with an octane number lower than 91 may be used, with reduced
performance". If there is truly a significant risk of detonation/engine
damage, as you describe below, then I should think that Acura would have
a more stern warning out this than what is in the literature.

> The issue here is compression ratio's and the very real risk of
> detonation if a high compression ratio engine runs on a fuel with too
> low an octane rating. There is no guarantee that detonation sensors
> (sometimes called "knock sensors") will catch detonation and retard
> fuel amounts and timing fast enough to save an engine when detonation
> occurs. Detonation can destroy pistons, rings, valves, connecting
> rods and rod bearings, basically trashing the engine and this damage
> can occur in fractions of a second.
>
> The cost of an engine replacement or rebuild would far exceed the
> small additional cost of premium fuel over the life of the vehicle.

True enough but one of the main reasons I'm looking to replace the gas
guzzling beast I am currently driving is to significantly lower my
monthly fuel costs. Having to pay roughly 25 cents more per gallon for
high octane in the tank of the RSX-S serously mitigates the improved
miles per gallon I'd be getting with this car. I want a sporty, fun-to-
drive car but also need to balance that with excellent fuel economy.

> Finally, it would make no sense to put a fuel in a performance
> oriented car which would then require you to drive it extremely gently
> and at risk of blowing the engine at any moment.

Point well taken and so maybe I need to take a closer look at the regular
RSX model, or something else entirely.

Thanks for the feedback.

> I'll leave it to others to address the fuel mileage issue.
>
> Paul
>
>
>
> On Sun, 18 Jun 2006 22:14:50 -0700, Joe McArthur
> <joemac@vfemail.spamblock.net> wrote:
>
>>I'm seriously considering buying an RSX Type-S and would like to know
>>a couple of things from people who own one, or have owned one. I read
>>somewhere that Acura recommends high octane fuel (91 if I remember
>>correctly) be used for the Type-S model. My question is What happens
>>if regular (87) octane is used instead? Can it cause any damage to
>>the engine? Will it reduce the gas mileage, and by how much? The
>>second question is what mileage per gallon are people actually getting
>>with this car? The sticker shows 23 City / 31 Highway, but my
>>experience with the 1990 Honda CRX Si that I used to own proved that
>>actual mileage can vary quite a bit from what is reported on the
>>sticker. I consistently got between 36 and 40 mpg with my CRX,
>>depending on the ratio of city to highway miles, but the sticker said
>>28 City / 33 Highway.
>>
>>Thanks, Joe